Pump



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ATTOIP/VL'VJ United States Patent 3,183,840 PUMP George E. Conover, Houston, Tex., assignor to Lynes, Inc., a corporation of Texas Filed Aug. 3, 1962, Ser. No. 214,565 4 Claims. (Cl. 103-49) This invention relates to new and useful improvements in pumps and control means therefor.

Double-acting pumps wherein a pair of pump cylinders are operably connected together for alternately providing a surge of pressure to a line are known. The doubleacting pumps heretofore known have been subject to surging or pulsations as the pressure feed is switched from one of the pump cylinders to the other. Such surging or pulsations not only produce an irregular outlet pressure but it also causes a rapid fatiguing of the hoses and'equipment subject to such surging or pulsations.

One object of the present invention is to provide a new and improved double-acting pump having a pair of pump cylinders wherein the pumping action and fluid outlet therefrom are extremely smooth and is substantially free from surging of pulsations. V

An important object of this invention is to provide a new and improved double-acting pump having a pair of pistons and cylinders in two power sections and including means therewith for initiating the power stroke with one of said pistons just prior to the completion of the power stroke of the other of said pistons so that there is no lapse in the power strokes of the two power sections.

Another object of this invention is to provide a new and improved double-acting pump having a pair of pump pistons and cylinders in a power section of the pump, wherein a closed fluid system is connected between the cylinders for a repeated movement from one of the cylinders to the other and back again as the pistons reciprocate, and wherein means are provided with the closed fluid system for controlling the quantity of fluid therein.

A particular object of this invention is to provide a new and useful control means for a pump which includes a pilot valve, an intermediate valve and a control valve for controlling the pumping action of such pump.

Another object of this invention is to provide a new and improved pump having a pumping section for pumping liquid at low or medium pressures and higher or medium volumes until a predetermined pressure is reached so as to rapidly fill a length of hose, a well tool or other volume, and for thereafter pumping liquid at relatively higher pressures and at relatively lower volumes to develop the higher pressures with a minimum of additional liquid. 7

Still another object of this invention is to provide a new and improved head assembly for a pump wherein such head assembly has the inlet and outlet fluid passages for the pump therein, such assembly being readily and quickly removable for replacement or repair.

It is yet a further object of this invention to provide a new and improved pump in which the packing and valves thereof are easily accessible with a minimum of dis-assembly.

A specific object of this invention is to provide a new and improved pump having two pistons and a mechanically actuated pilot valve therewith which is adapted to be contacted at the forward end of the stroke of one of the pistons for initiating the reversal of the movement of such piston.

Another object of this invention is to provide a new and improved pump having a mechanically actuated drain 3,183,84fl Patented May 18, 1965 ICC valve therewith which is adapted to be actuated only when one piston thereof exceeds its operating rearward limit to cause a draining of some fluid from a closed fluid system connected with such pump.

Still a further object of this invention is to provide a new and improved double-acting pump having a pair of connected pump units each of which has a power section and a pumping section, said power sections alternately supplying power to said pumping sections so that said pumping sections deliver fluid at a relatively low pressure and high volume for an initial period and at a relatively high pressure and low volume at a subsequent period.

The preferred embodiment of this invention will be described hereinafter, together with other features thereof, and additional objects will become evident from such description.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and where- FIG. 1 is a plan view, partly schematic, illustrating the apparatus of this invention;

FIG. 2 is an elevation of one of the two pumping units of the pump of this invention;

FIG. 3 is a view, partly in section and partly in elevation, illustrating the details of the valves for controlling the power fluidused with the pump of this invention, and including schematically the flow lines for such fluid;

FIG. 4 is a sectional view taken on line 4-4 of FIG. 2

for illustrating the details of the pumping section of one of the pumping units of the pump of this invention;

FIG. 5 is a sectional view of one-half of the cylinder head of one of the pumping sections and is taken on line 5--5 of FIG. 4 to illustrate the details of the high pressure portion of such head;

FIG. 6 is a sectional view of one-half of the cylinder head of one of the pumping sections as taken on line 66 of FIG. 4 to illustrate the low pressure side of said head; and

FIG. 7 is a detailed view, partly in section and partly in elevation, illustrating the discharge control valve for use with the apparatus of this invention.

In the drawings, the pump of this invention includes a pair of pump units P-1 and P-Z. The pump unit P-l includes a power section A1 and a pumping section B-l. The pump unit P-2 is identical with the pump unit P-1 and includes a power section A-2 which corresponds with the power section A-1. Also, the pump unit P-2 includes a pumping section B-2 which corresponds with the pumping section B-l. Briefly, the pump units P1 and P2 are supplied with liquid or fluid under pressure through line 10 from any suitable source and are alternately reciprocated so as to provide a discharge alternately from the pump units P1 and P-2 for providing a substantially constant discharge of pressure fluid through line 11. In order to control the alternate admission of the liquid under pressure from the line 10 to the power sections A-1 and A-2 alternately and to also provide other advantages hereinafter set forth, the pump apparatus of this invention includes a pilot valve V-l, an intermediate valve V2, a control valve V-3 and a drain valve V-4. For regulating the discharge of the fluid from the pumping sections B l and B-Z, a discharge control valve DV is provided so that liquid is discharged through line 11 initially at low pressure high volume and subsequently at high pressure low volume as will be more fully explained. Such fluid delivered through line 11 as indicated in FIG. 1 may be used to actuate inflatable packers or other well tools or devices as desired.

Considering the invention more in detail, reference is made to FIG. 2 which illustrates the pump unit P-l mounted upon brackets or channel members 12 which in turn are welded or are otherwise secured to a platform or skid S. Preferably, both of the pump units P-1 and P2, with the accompanying valve controls are mounted on the common platform or ski-d S, although it will be appreciated that such is not essential. Since the pump units P-1 and P2 are identical, only the unit P1 is described in detail. The same numerals as are used to identify the parts of the unit P4 are used to identify the same or corresponding parts of the unit P-2 except that such numerals are followed by a prime mark for the unit P-2.

Referring in particular to FIGS. 1-3, the power section A-1 of the pump unit P-1 includes a housing 14 which is of conventional construction. A piston 15 (FIG. 3) also of conventional construction is mounted within the housing or cylinder 14 for reciprocation during the power strokes and the return strokes. A piston rod 16 is connected to the piston 15 and extends through the housing 14 and a casing 17 (FIG. 2) to a piston body 20 which operates within the pumping section B-l, as will be explained. The housing or cylinder 14 has fluid openings 14a and 14b for the inlet and return of fluid. It is to be noted that the heads or end sections 13 and 19 on the cylinder or housing 14 are preferably held with tie bolts 21, but any other suitable means may be provided. The unit P-2 has identical parts to the unit P1 in the preferred form of the invention, including in particular a piston 15' which reciprocates in cylinder 14 In order to control the alternate power strokes with the pistons 15 and 15, the valves V-l through V-4 are empioyed. The pilot valve V-1 may be of any known construction, but as illustrated in FIG. 3, such valve V-l is a mechanically actuated spool type valve which may be pushed either upwardly or downwardly. The pilot valve V- 1 includes a valve body having an inlet port 25a in communication with the pressure supply line 10. The body 25 has a bore or chamber 25b which is adapted to receive the pressure supply fluid from the port 25a. The spool valve member 26 having an upper spool surface 26a and a lower spool surface 26b is positioned within such chamber 25b for upward and downward movement upon actuation, as will be explained. The upper spool surface 26a is disposed opposite a port 250 so as to close same when the spool valve member 26 is in the center position as shown in FIG. 3. Likewise, when the valve member 26 is in such center position, the lower spool surface 26b closes port 25d in the valve body 25 as shown. The valve body 25 also has an outlet port 25c which is in communication with the bore of the valve body 25 below the port 25d. A fluid channel 25 establishes communication between the bore area of the housing or body 25 above the port 25c and the port 2512.

The valve member 26 is held in the center or intermediate position shown in FIG. 3 by resilient members or springs 27 and 28. The valve member 26 is adapted to be pushed downwardly from its center position of FIG. 3 so as to cause a compression of the spring 28 and is adapted to be pushed upwardly from the position of FIG. 3 so as to cause a compression of the spring 27. The downward movement of the valve member 26 is effected by the downward movement of an actuator assembly 30, the details of which will be explained more fully in connection with FIG. 4 of the drawings. Such actuator assembly 30' is caused to move downwardly by contact with a cam ring or element 31' carried on the piston rod 16 (FIG. 3).

The upward movement of the valve member 26 is effected by the upward movement of an actuator assembly 30. The actuator assembly 30 is identical with the actuator assembly 30' and it is caused to move upwardly by a cam ring or element 31 carried on the shaft 16.

Thus, when the cam ring or element 31' moves the actuator assembly 30' downwardly, the spool valve member 26 moves downwardly from the position shown in FIG. 3 so that the fluid under pressure in line 10 flows through the inlet port 25a, the chamber 25b and then passes outwardly through the port 25d into connecting tube or line 32 for flow to the intermediate valve V-2, as will be more fully explained. When the supply of pressure fluid is thus being discharged to line 32, an exhaust or return fluid flow occurs from line 33 and valve V-2 through port 250 and lines 25 25e for return through the sump line 34 to the sump 35 (FIG. 1) or any other similar tank.

When the valve V-1 is in its raised or upper position, the inlet pressure fluid from the line 10 flows through the port 25a and out through the port 250 to the line 33. The return or exhaust fluid flows from the line 32 into the port 25d and then out through the opening or port 25a to the sump line 34. When the valve V-i is in the center position as shown in FIG. 3, no flow in either direction through the valve occurs. It should be noted that the flow line or passage 25 in the valve body 25 bypasses around the inlet port 25:: so that there is no direct communication therebetween. I

The valve V-Z includes a valve body which has an inlet port 40:: connected to a pressure supply line 13:: leading from the main pressure supply line 10. Such port 49a communicates with the valve bore or chamber 40b in which a triple spool valve member 41 having an upper spool surface 41a, an intermediate spool surface 41b, and a lower spool surface 410 is adapted to reciprocate upwardly and downwardly. The valve body 40 has another port 400 which is connected to the line 32 for either admitting fluid under pressure or discharging fluid from the valve body 40. v A similar opening 40d is provided at the lower end of the valve body 40 and it has connection with the line 33. Another port 4% is in communication with the bore 40b below the spool surface 41a while another port 40 is in communication with the bore 4% above the spool surface 410. The port 40e connects with a flow line or tube 42 which extends over to the control valve V-3 as will be explained. Also, an orificemember 43 is connected between the line 42 and the line 32 for a purpose to be hereinafter explained. The port 43 is connected with a flow line 44 which extends to the valve V3. Also, the line 44 is connected to the line 33 with an orifice control 45 therebetween for a purpose to be hereinafter explained.

The valve V2 also has an outlet port 40g and a connecting passage 40h which connect with a sump line 34a in communication with the sump or return line 34.

When the pilot valve V-1 has been mechanically actu ated to move same downwardly from the center position of FIG. 3 so as to cause the pressure supply fluid 10 to flow through the line 32 as indicated by the arrows in FIG. 3, fluid pressure acts downwardly on the spool valve member 41 when the valve V1 is actuated downwardly, the valve member 41 is in its raised or upper position and therefore the fluid flow from line 32 enters the port 40c and exerts a downward force on such member 41 which attempts to shift same to the lower position (FIG. 3). As port 25d is opened more fully, a point is reached where flow into line 32 from the port 25d is faster than the flow out of line 32 through orifice 43. Also, at the same time that the pressure from line 32 is acting on the upper end of the spool surface 41a of the member 41, the port 40.4 is open through the line 33 to the sump or drain line 34 since the line 33 is connected through the port 250 to the discharge passage or channel 25 and the discharge port 25c. As the port 25c is opened more fully, a point is reached where the flow from line 33 through port 25c is faster than the flow through orifice 45. At such point, the opening in port 25c is larger than the opening in orifice opening 45 so that the fluid in the line 33 and the area below the valve member 41 drains through line 34 as the pressure above the valve member 41 is applied from line 32. Therefore, when the valve member 26 of the pilot valve V-l is mechanically moved downwardly, the intermediate valve V-2 is shifted with the hydraulic liquid, causing the valve member 41 to snap downwardly to its lower position shown in FIG. 3.

When the valve member 41 reaches its lower position as shown in PEG. 3, the pressure fluid from the line a then passes as indicated by the arrows in FIG. 3 through the valve chamber 4% and is discharged outwardly through the line 42. The line 44 is open to drain or sump through the line 84a. It is also to be noted that the pilot valve V-d returns to its central position after the valve V-2 has shifted, but the valve V2 remains locked in its down position by the fluid pressure in the line 10a which passes through ports 40a and '40:; in valve body 40 to line 42, and from there it is conducted back through orifice 46 to augment the pressure in line 32 to lock or hold down the valve member 4 1. When the valve V-1 is moved upwardly, the reverse action takes place, and the valve member 41 is moved upwardly from the position shown in BIG. 3 by the initial pressure fluid which is supplied through the line 36 and the return fluid drains through the line 42 and the line 34a. After the valve has been actuated, it in turn is held in its upper position by fluid pressure active through 10a which passes through ports'40a and 40 in valve body 40 and is then idischargedthrough line 44 and orifice 45 to augment the pressure fluid in line 3-2 acting to hold member 41 in its upper position.

Of course, the initial pressure fluid through line 33 is supplied from line 10 and through ports a and 25c when valve member 26 is moved upwardly by cam ring 31 striking assembly 30. l

The valve V-3 is the control valve for the power sections A41 and A-2. The control valve V-c has a valve body 50 having and inlet port 50a and a valve bore or chamber 50b. -A triple spool valve member 51 having a right spool surface 511;, an intermediate spool surface 51b, and a left spool surfaoe51c is located in the chamber 50b for movement to the left and right. Such movement could of course be up and down, depending entirely upon the position of the valve V-'3. Such is of course also true with respect to the other valves V-al, V-2, .and V4, the particular positions being shown merely for reference and by way of example in FIG. 3. i i

The valve body 50 has another opening 50c connected to the pipe or tube 42. -A similar opening 5003 at the other end of the body 50 is in communication with the fluid line or tube '44-. The opening 50a is in fluid communication with a fluid pressure line 10b which is connected to the main pressure line .10. The valve body 50 has another port or opening 50c which is in fluid communication with a drain or sump line 34b which con.- nects with the drain or sump line 34.

The valve body also has a port 567 which is in fluid communication with the chamber 50b and :a flow line or tube 52 leading to the opening 14a of the power section A 1 (FIG. 3). Another opening 59g in the body 50 is in comunication with a flow line or tube 53 connected to the opening 1 4a of the power section A-2. The valve body 50 lalsohas a valve passage 50h which communicates between the outlet opening 502 and valve opening 50f when the valve member -41 is in the extreme right position. i

As shown in RIG. 3, the valve V- 3 is in its left position with the fluid flow in the direction of the arrows so that the pressure fluid from the line 10b is transmitted to the piston :15 for urging it to the left as viewed in FIIG. 3. During such power stroke with the piston 15, the fluid on the power side (left side as viewed in FIG. 3) of the piston ;15 is forced through the opening 14b and flow line or pipe 54 to opening 1=4b so as to force the piston 15 to a return position (to the right as viewed in FIG. 3). The exhaust fluid to the right of the piston 15' is thus drained or returned through the line 53 to the valve opening 50g and then out through the opening 502 to' the drain line 34b. The valve member 51 is held in the left position by fluid under pressure in the line 42 at which time the line 44 is open to the drain line 34a through the valve V2.

In the preferred form of this invention, the width of the central spool surface 51b is less than the width of the annular groove 50d so that as the valve member 51 moves from the left'to the right, and vice versa, there is an intermediate point at which the pressure fluid from the line 10b is directed to both of the openings SW and 50g for flow through both lines 52 and 53. Therefore, during such period of time, both of the pistons 15 and 15 are actually being urged in a power direction (to the left in FIG. 3). Such simultaneous power action occurs just prior to the time the piston on the power stroke is ready to complete such power stroke and return in the opposite direction on the return stroke. For example, just prior to the time the piston 15' reaches the end of its power stroke, the cam ring or element 31' moves the actuating assembly to trip the pilot valve V-1 which causes the intermediate valve V2 to shift and thus to shift the valve V-3. Such shifting of the valve V'3 thus is timed to occur prior to the completion of the power stroke of the piston 15'. The fluid pressure in the line 42 causes the valve member 51 to move to the left and through the intermediate position during which time the fluid under pressure from the line 10b is caused to flow to both of the cylinders E14 and 114. Thus, the power fluid to the piston- 15 continues, but also the power to the piston 15 begins a to take effect to start to return the piston 15 on its power stroke. As soon as the intermediate spool surface 51b reaches its left position as shown in FIG. 3, then the fluid from the pressure line 10b flows only to the cylinder 1-4 and the piston 15. The piston 15' is no longer being forced with a power fluid but instead is opened to drain through the line 53. Therefore, the piston '15 continues to move in its power stroke as the piston 15' returns for its next stroke. It is therefore significant that the valve V-3 causes both of the pistons 15 and .15 to move in a power direction just prior to the end of the power stroke for each of such pistons so as to prevent surging of the guid being pumped by the pumping sections B-1 and It will be understood that when the piston 15 reaches a point prior to the end of its power stroke, the cam elementor ring 31 will contact the actuating assembly 30 to instantaneously open the pilot valve V=1 to transmit pressure fluid through the valve V-2 to the control valve V-3 so as to shift the valve member 51 from the left position to the right "position. During such shifting of the valve member '51, it again goes through the intermediate stage at which time there is a pressure fluid through both of the lines 52 and 53 due to the smaller width of the surface 51b as compared to the width of the annular groove k. The piston 15 thus starts its power stroke before the power is released from the piston 15. Thus, pressure fluid flows from line 10b to line '52 and line 53 until the valve member 51 is at its right position at which time all flow from line 10b is to line 53. 'This causes the piston 15 to continue its power stroke while the line 52 is connected to theexhaust or sump line 3412 so that the piston 15 returns to the right. Such reciprocation of the pistons 15 and 1-5 alternately continues automatically due to the mechanical tripping of the pilot valve V-1 with the cam elements 31 and 31' alternately.

During the period of overlapping of the stroke of pistons 15 and 15', liquid is discharged from both cylinders 14 and 14' through 14b and 14b, respectively, and into line 54. The accumulator 56 communicates with line 54 for receiving this liquid. Such accumulator 56 may be a. flexible hose with a closed end that is adapted to contract and expand to receive the volume of the liquid in the closed system.

sasasao As previously noted, the cylinders (14 and 14' are connected in a closed system .at their power sides through the line 54- which extends from the opening 14b to the opening 1=4'b. In order to be certain that the closed fluid system on the power side of the pistons 15 and 15:" remains full of liquid at all times, :a metering valve 55: is provided frornline 10b so as to constantly meter or feed into the line 54 small amounts or quantities of liquid from the supply pressure line 16 In the event too much fluid is present in the closed fluid: system of the pistons and 15', such excess fluid would result in an excessive movement of the pistons 15 and 15' alternately to the rear or to the right as viewed in FIG. 3 on their return strokes. To avoid such occurrence, the drain valve V-4 is provided (FIG. 3). The valve V-4 includes a valve body 60 having a bore or chamber 66a in which a spool valve member 61 reciprocates. Such spool valve member 61 has an upper spool surface 61a and a lower spool surface 61b. The valve body 60 has ports 60b and 600 which are in communication with the closed system line 54. When the spool valve member 61 is in a lowered or down position, the fluid line or pipe 54 is in communication with the opening 6% and permits flow above the spool member 61a through a flowpassage 60d in the valve body 60 to an outlet port 602.. The outlet port 600 is connected to a sump line 34' which may go to the sump 35 or another sump (not shown). When the valve member 61 is in the raised or upper position, the fluid line 54 is in communication with the port 60c so that fluid may flow below the spool surface 61b and out through the port 6% to the drain or sump line 34.

The valve member 61 is moved to the raised position from the center position shown in FIG. 3 by a coaction between the cam element 31 and an actuating assembly 62. Such actuating assembly 62 is identical with the actuating assembly 30 and merely serves to transmit the movement of the cam 31 upwardly to cause the upper spring 63 to be compressed, and also permitting the flow previously described for the valve in the upper position. Such contact of the element 31 with the actuating member 62 does not occur unless there is an excess of fluid in the closed fluid system which is tending to cause the piston 15 to move too far rearwardly or to the right on its return stroke. However, if such excess volume is present, then such excess volume moves the piston 15 far enough to the right on its return stroke to cause the cam element 31 to contact the actuating'assembly 62 which actuates the valve V-4 to release the excess volume through the line 34'. The excess return stroke of the piston 15 is thus prevented while maintaining the closed fluid system full of liquid at all times.

The downward movement of the valve V4 is caused by an engagement of the cam element 31' with the actuating assembly 62' which is identical with the assembly 62. Similarly, the cam element 31' moves the actuating assembly 62 downwardly only when there is an excess of fluid in the closed fluid system tending to move the piston 15 beyond a predetermined point on its return stroke. Therefore, it can be appreciated that if there is excess liquid in the closed fluid system, it will be released on either or both of the return strokes of the pistons 15 and 15'.

Although the power sections A-1 and A-2, including their control valves V-l through V-4, may be used with various pumping sections, it is preferred to use the pumping sections B-1 and B2 shown in the drawings. Only the pumping section B1 is shown in detail (FIGS. 46) since the pumping section 13-2 is identical therewith.

The pumping section B-1 is so constructed that it is capable of delivering a low or medium pressure fluid at a high or medium volume during an initial pumping period while subsequently delivering a relatively high pressure fluid at a lower volume. The delivery of fluid under such conditions is particularly desirable for the inflation of inflatable well packers, but it is also usable and desirable in other tools and uses.

Referring now to FIG. 4 in particular, the pumping section B1 has a forward cylinder 65 and a rear cylinder 66, which together form the cylinder of the pumping section B-1. The forward cylinder 65 has external threads 65a which are threaded engagement with internal threads 66a on the rear cylinder 66. A packing 67 carried between metal rings 67a and 67b is adapted to be held in position between the end 65b of the forward cylinder and an annular shoulder 66b of the rear cylinders 66. Such packing 67 provides an external seal for the piston body 20 during its reciprocation, as will be more evident hereinafter. It is to be particularly noted that the packing 67 is readily removable by simply unthreading the cylinder 65 from the cylinder 66.

The piston body 20 reciprocates within the cylinder provided by the cylinder sections 65 and 66. The cam element 31 is preferably held or connected to the piston body 20 for movement therewith. To this end, the piston rod 16 is threaded at 16a into the piston body 20, and a shoulder 1612 on the shaft or rod 16 engages the cam ring or element 31 to securely hold same to the piston body 2t). It will be understood that there normally is no liquid in the cylinder section 66 to the right of the packing 67 (as viewed in FIG. 4). Fluid is present in the bore 20a of the piston body 20, as will be explained.

As previously pointed out, the cam element 31 contacts the actuating assembly 30 upon the forward or power stroke. The actuating assembly 30 illustrated in PEG. 4 is provided with a contact head 300 which is slidably mounted in a fixed sleeve 30b. Such sleeve 30b is welded or otherwise secured to the cylinder section 66. A spring 300 is provided within the bore of the contact sleeve or member 300, and suitable openings 30d are provided to prevent fluid lock within the bore of the contact member 30a. Upon an upward movement of the contact member 30a, a cushioning eifect is provided by the resilience of the spring 36c and such upward movement is transferred to a plunger 30e connected to a rod 30 which is in contact with or secured to the spool valve member 26 (FIG. 3). An outer housing 36g is preferably provided for enclosing the actuating rod 30 and for connecting to the body 25 or" the valve V1.

It will be understood that the actuating assemblies 30', 62, and 62' are preferably identical with the assembly 30. In this connection, it is to be noted that the cam element 31 contacts the actuating assembly 62 upon the return stroke of the power section and the pumping section only if an excess of fluid is in the closed fluid system of the power section, as previously explained in connection with FIG. 3. Such contact by the cam 31 with the actuating assembly 62 is illustrated in FIG. 4.

The forward cylinder 65 is provided with a closed forward end 650 which has a longitudinal center opening 65d therethrough. Such opening 65d is adapted to receive a flow separator and guide tube 70 which defines a plunger that extends into the cylinder 65 and also into the bore 202; of the piston body 26. The tube 70 is secured to the closed end 65c by means of a retainer plate 71 and a locking nut 72 which is threaded on a threaded shank 76a of the tube 70. The flange or plate 71 also serves to hold a cylinder head 75 in position on the end of the cylinder 65 as will be more fully explained. With such construction, the removal of the nut 72 permits the removal of the plate 71 and the entire cylinder head 75 from the cylinder 65. Then, upon the unthreading of the cylinder 65 at the threads 65a from the cylinder 66, the packing 67 is accessible, as previously explained, the tube 70 may be withdrawn or made available for inspection. Likewise, the seal 73 of rubber O-rings or any other suitable packing is accessible by the removal of the plunger 70. Such seal 73 provides a fluid seal with the external surface 76b of the plunger or tube 76 during the reciprocation of the piston body 20 relative to the tube 70.

During the pumping stroke with the piston body 20,

there are two piston areas acting which are maintained separately from each other by the seal 73. Thus, the fluid within the bore 65a is urged forwardly as the piston body 20 moves forwardly. Also, during such forward movement of the piston body 20, the fluid within the bore 20a of the piston body 20 is urged forwardly through the bore 70c of the tube or plunger 70. 1

The low pressure high volume liquid is pumped or delivered from the cylinder area between the bore 65:; and the external surface 70b of the tube 70 through one or more ports 65 and an annular groove 65g connected therewith (FIGS. 4 and 6). The cylinder head 75 has a square external shape or any other suitable shape, but it has an internal cylindrical bore 75a which is adapted to fit over the external surface of the cylinder 65 as shown in FIGS. 4 and 6, with appropriate fluid seal rings or means 76 provided.

The cylinder head 75 includes not only the fluid passages for controlling the discharge or delivery of the fluid from the pumping section B-l, but it is also includes the valves for such control. Also, as will be apparent from the drawings (FIGS. 5 and 6), the cylinder head 75 is formed by drilling straight holes int-o or through the body thereof so that the manufacture of such head 75 is simplified.

Thus, the cylinder head 75 has a straight discharge opening 75b which is in communication with the annular groove 65g for receiving the low pressure high volume fluid from the cylinder 65. The opening 75b is plugged to close its outer end as indicated by the plug 76. Such opening 75b is in fluid communication with a passage 75c perpendicular thereto and which has a counterbore 75d. A check valve sleeve 77 is mounted in the counter-bore 75d with openings 77a, 77b and 770 therethrough. Therefore, fluid flowing into the passage 75b flows through one or more of the openings 77b and upwardly through the openings 77a into the passage 75c. A ball check valve or any other suitable check valve means such as indicated at 78 is urged to a closed position by a spring 79 so that the fluid which flows into the passage 75- is prevented from flowing downwardly past such valve 78 into a suction line 75e. For ease of assembly, the ball valve 78 preferably seats upon a removable valve seat 80 which is supported on a removable plug 81 having suitable ports 81a therethrough for communicating the bore 81b thereof with the suction passage 75e. Such passage 75e is plugged as indicated at plug 82. Another fluid passage 75 is also preferably provided for the flow of the pressure fluid from the annular groove 65g through the openings 77c and upwardly into the passage 750 when the ball valve 78 is closed as shown in FIG. 6. A plug 83 closes the outer end of the passage 7 5 The flow passage 750 has an upper counterbore 75g which is adapted to receive a valve seat 84 which is held in place by'a threaded retaining plug 85. Such retaining plug 85 has a bore 85a and lateral openings 85b. A spring 86 urges the ball valve 87 downwardly to a closed position. The spring 86 thus holds the ball valve 87 closed on the suction stroke but pressure into the line 75c from the groove 65g on the power or pumping stroke of the unit B-l overcomes such spring 86 to open the valve 87. When the valve 87 is in the open or raised position, the fluid under pressure flows from line 750 into fluid passage 75h and then outwardly through a flow line 88 connected laterally to the passage 75h (FIGS. 1 and 6). The passage 75h is plugged as indicated by the plug 89. Also, it should be noted that the passage 75h is shown as extending only a portion of the way through the cylinder head 75, but in actual practice, it would normally extend the entire distance or thickness of the head 75 and would be plugged at both ends.

On the suction or return stroke of the piston body 20 'in the pumping section B-l, fluid is drawn from the sump 35 or other source through a flow line 90 (FIG. 1) and suction inlet hose or line 91. The force of the fluid in the line 75e acts against the ball valve 78 and is suflicient to unseat the ball valve 78 and open same for flow into the cylinder 65 through the lines 75f and 75b. The check valve 87 remains closed during the suction stroke.

The high pressure low volume liquid is delivered from the pumping section B1 through the bore 70a of the tube 70 by means of one or more ports 70d which are in communication with an annular groove 65h in the cylinder 65. Suitable -O-rings 92 preferably are provided to seal off such flow through the ports 70d into the annular groove 65h (FIG. 4). The annular groove 65h communicates with one or more flow passages 65k (FIGS. 4 and 5) and an annular groove 65m. Such annular groove 65m is in fluid communication with laterally extending ports 75k and 75m for the discharge of the high pressure fluid into such passages 75k and 75m.

The passages 75k and 75m are in communication with a longitudinally extending fluid passage 750 which is provided with a counterbore 75p. A check valve sleeve 92 having an upper opening 92a and side openings 92b and 920 is mounted in such counterbore 75p. The passage 75k is plugged with a suitable plug 93 and the passage 75m is plugged with a suitable plug 94 so that the pressure fluid flows from the passages 75k and 75m through the openings 92b and 920 and upwardly through the opening 921: into the passage 750. The pressure fluid is prevented from flowing downwardly into a lower fluid passage 75s by means of a check valve 95 which is urged downwardly by a spring 96.

Such valve 95 functions in the same manner as the valve 78 heretofore described in connection with FIG. 6 and serves to separate the pressure and suction sides of the high pressure system. The ball valve 95 is seated upon a cylindrical valve seat 96 which is removably held in place by a removable plug 97. The plug 97 has a bore 97a and ports 97b therethrough for the flow of suction fluid during the suction stroke of the piston body 20, as will be explained. The passage 75s is plugged off with a plug 98.

The fluid passage 750 has a counterbore 75t in which a valve seat 99 is positioned for seating a check valve 100. The valve seat 99 is removably held in place by a removable plug 101. The valve 100 is urged downwardly by a spring 102 of predetermined pressure for holding same closed during the suction strokes and allowing same to open during the power or pumping strokes of the piston body 20. On the pumping strokes, the fluid in the fluid passage 75o forces the valve 100 upwardly against the spring 102 so that the fluid flows into the bore 101a and through one or more ports 101b into a lateral fluid passage 75v. Such fluid pass-age 75v is plugged at 103 and is also closed at its other end so that the fluid in the passage 75v is discharged through discharge line 105 for flow to the discharge valve DV as will be more fully explained.

On the suction stroke of the pumping section B-l, liquid is drawn into the bore 70c of the tube 70 and the bore 20a of the piston body 20 through the suction line 91 which connects with the line 90 and the sump 35 or any suitable source of liquid. During the suction stroke, the valve 95 and the valve 78 are unsea-ted by the fluid from the suction line 91 as such fluid is drawn into the bores 20a and 65e.

As indicated in FIG. 7 and also in FIG. 1, the flow lines or pipes 88 and 105 supplying the low and high pressure, respectively, from the pump section B1 are connected with the discharge control valve DV. It should also be pointed out that the pumping section B-Z has a line 88' connected with the valve DV at the same inlet point as the line 33 as indicated in FIG. 7. Likewise, the pumping section B-Z has a line 105' which is connected to the valve DV at the same inlet point as the line 105. It will be understood that since the pumping sections B-1 and B-2 operate alternately, the liquid is supplied to the valve DV alternately through the lines 88 may be around to gallons per minute.

l l and 105 from the section B1 and through the lines 88' and 105' from the section B-2. Thus, on one pumping stroke, the fluid pressure is supplied to the valve DV through the lines 88 and 105 while on the other pumping stroke the fluid under pressure is supplied to the valve DV through the lines 88' and 105'.

The'valve DV has a valve body 110 which has a fluid passage 110a therein in fluid communication with the tubes or flow lines 88 and 88'. One end of the flow passage 110a is connected with a pressure relief valve or unloading valve 112, the purpose of which will be hereinafter described. This valve is described and claimed in the copending application of Edwin E. Hoffman filed May 24, 1962 and bearing Serial No. 197,402, which application and invention belong to the assignee of this invention. The other end of the passage 110a is in communication with a longitudinal passage 1110b in the valve body 110; Such valve passage 11011 is counterbored at 1100 to receive a valve seat 114 which is removably held in place by a removable plug 115. A ball check valve 117 is mounted in the bore 115a of the hollow plug 115 for seating in contact with the annular edge of the valve seat 114. A resilient spring 118 acts to urge the ball valve 117 downwardly with a predetermined pressure. When the pressure is sufficient to open the valve 117, the fluid from the flow line 110a flows upwardly through the flow passage 1410b and openings 115i) into a flow passage 110d. T he flow passage 110d is in communication with a longitudinal flow passage 1102 which is connected to the working pressure line or discharge 11.

During the initial phase of the power stroke with the pumping section B-l, the liquid is delivered through both of the lines 88 and 105 to the valve DV. At that time, the liquid is delivered through the line 11 to any tool or object to be actuated by such pressure. For example, if it is desired to inflate an inflatable packer, the line 11 is connected to such inflatable packer and the liquid under pressure is supplied from both of the flow lines 88 and 105 through the valve DV to thereby supply a relatively high volume of the liquid to such packer. By way of example, the pressure at that point may be around 2,000 to 3,000 pounds per square inch, and the volume delivered When the inflatable packer is almost inflated, a greater pressure will develop in the flow line 11 and in the valve DV which will reach an amount in excess of 2,000 or 3,000 pounds per square inch or such other predetermined pressure at which the pressure relief valve 112 is set to open. When the pressure relief valve valve 112 opens, the fluid in the line 110a drains therefrom rather than flowing through the check valve 117 since the pressure in the line 110a is not high enough to hold the valve 117 open.

Therefore, the volume of liquid entering the line 110a through the line 88 does not reach the line 11 so that the only liquid reaching the line 11 is that which enters through the tube 105. Furthermore, higher pressures continue to be developed in the line 11 as the inflatable packer or other object becomes more nearly full. Pressures of 20,000 pounds per square inch or greater may be obtained.

In summary, in the operation of the apparatus of this invention, the pumping units P1 and P-2 operate alternately and are actuated by a source of liquid under pressure supplied through the fluid line 10. Such fluid is admitted from the line 10 to either the piston 15 or the piston 15' so that one of such pistons performs a power stroke while the other is on the return stroke, except that power fluid is supplied to both pistons near the end of each power stroke to prevent surging, as previously explained. The valve V-S is shifted to change the flow of the pressure from the power section A-l to the power section A-2, and vice versa; by a tripping of the pilot valve V-1, which mechanically moves to initiate hydraulic flow through the hydraulic intermediate valve V2. The hydraulic intermediate valve V2 functions to control the flow of the pressure supply fluid to the valve V-3 which in turn regulates or controls the flow to the power sections A-1 and A-2'.

The valve V-4 serves as a drain valve to prevent the accumulation of an excess of fluid in the closed fluid system of the power sections A-1 and A-2, as previously explained.

The valve DV controls the liquid delivered to line 11 so as to initially deliver the liquid at a low pressure and a relatively high volume while subsequently delivering the liquid at a relatively high pressure and low volume. It will 'be understood that the pressure and volume delivery from the pumping sections B-1 and B-2 may be constant or variable as desired, but in the preferred form of the invention the conditions of initial low pressure and high volume followed by subsequent high pressure and low volume are preferred. 7

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. A double-acting pump having a pair of power sections and a control means therewith for controlling the pumping action of the pump, including:

(a) a control valve for controlling fluid inlet to the pair of power sections for alternate pumping with said sections,

(b) an intermediate valve operably connected with said control valve for hydraulically. shifting same, and

(c) a pilot valve adapted to be mechanically moved for controlling hydraulic'fluid flow to said intermediate valve to control the movement thereof.

2. The structure set forth in claim 1, including:

(a) fluid flow passage means connecting said pilot valve and said intermediate valve, and

(b) said passage means to each side of said intermediate valve including orifice means for regulating the shifting of said intermediate valve to different positions.

3. A double-acting pump having a pair of power sections and a pair of pumping sections and a control means therewith for controlling the pumping action of the pump, including: 2

(a) a control valve for controlling fluid inlet to the pair of power sections for alternate pumping with said sections,

(12) an intermediate valve operably connected with said control valve for hydraulically shifting same,

(0) a pilot valve adapted to be mechanically moved for controlling hydraulic fluid flow to said intermediate valve to control the movement thereof, and

((1) means on said pumping sections for alternately mechanically moving said pilot valve substantially at the end of the power stroke of each of saidpumping sections.

4. A double-acting pump, including:

(a) a pair of pumping units,

(b) each of said pumping units including a power section and a pumping section,

(0) a closed fluid system connecting the power ends of said power sections,

(d) means associated with said power sections for controlling the quantity of fluid in said closed fluid system, said last named means including:

(1) an accumulator adapted to contract and expand to compensate for changes in the quantity of fluid in the closed system,

(2) means for metering fluid into said closed system to maintain an adequate quantity of fluid therein at all times, and

(3) means for draining fluid from said closed sys- 13 14 tern in the event the quantity thereof becomes 2,866,415 12/58 Mortelius 103-49 excessive. 2,890,658 6/59 Hjarpe 103-49 2,897,762 8/59 Houvener 103-49 References C1ted by the Examlner 2,996,014 8/61 Lee 10349 UNITED STATES PATENTS 5 1 551 430 25 Gruman 103 153 LAURENCE V. EFNER, Primary Examiner.

2,141,731 12/38 Wolfrom et a1. 103-49 OB M. WALKER, Examinen 2,411,438 11/46 Lane 103158 

1. A DOUBLE-ACTING PUMP HAVING A PAIR OF POWER SECTIONS AND A CONTROL MEANS THEREWITH FOR CONTROLLING THE PUMPING ACTION OF THE PUMP, INCLUDING: (A) A CONTROL VALVE FOR CONTROLLING FLUID INLET TO THE PAIR OF POWER SECTIONS FOR ALTERNATE PUMPING WITH SAID SECTIONS, (B) AN INTERMEDIATE VALVE OPERABLY CONNECTED WITH SAID CONTROL VALVE FOR HYDRAULICALLY SHIFTING SAME, AND (C) A PILOT VALVE ADPATED TO BE MECHANICALLY MOVED FOR CONTROLLING HYDRAULIC FLUID FLOW TO SAID INTERMEDIATE VALVE TO CONTROL THE MOVEMENT THEREOF. 